1. Field of the Invention
This invention relates generally to apparatus used in conjunction with respiratory support systems. More specifically, the present invention relates to a method and apparatus for the attachment of accessory devices to a respiratory support system. Even more specifically, the present invention relates to a ventilator manifold of a respiratory system which accommodates the attachment and detachment of accessory devices therewith without interrupting or inhibiting the continuous respiration assistance being given to a patient by the respiratory system.
2. Prior Art
Respiratory systems used for the ventilation of critically ill patients are now commonly used in medical facilities. Typically, a prior art respiratory system includes a tracheal tube, positioned either directly, or through the nose or mouth, into the trachea of a patient, a manifold connected to the tracheal tube at one port position thereof, and a source of breathable gas connected at a second port thereof. The purpose of the respiratory system is to assist the patient in maintaining adequate blood oxygenation levels without over taxation of the patient's heart or lungs.
While a patient is attached to a respiratory system, it is periodically necessary to remove fluid from the patient's trachea or lungs. In the past, it has been necessary to disassemble part of the respiratory system, either by removing the manifold, or by opening a port thereof, and inserting a small diameter suction tube down the tracheal tube and into the patient's trachea and lungs. The fluid was then suctioned from the patient and the suction catheter was removed and the respiratory system reassembled. Due to the resulting interruption in respiratory support, a patient's blood oxygen often dropped to an unacceptably low level during the suctioning procedure, even when other previously known breathing assisting efforts were simultaneously provided.
One solution to the above problem, which is generally exemplary of the prior art, is shown in U.S. Pat. No. 5,073,164 by Hollister et al. in which the ventilator manifold includes a port thereon which is adapted to receive a connector of the suctioning device. The suctioning device positions a suction catheter within the manifold without substantial manifold pressure loss. The suction device includes an envelope which is positioned around the suction catheter in order to prevent contamination of the suction catheter surface which is intended to be inserted into the patient's trachea and lungs. Although this type of ventilator manifold and suctioning device connection allows continuous respiratory support of the patient during suctioning of fluid from the patient's trachea and lungs, there nevertheless remain several drawbacks associated with its use. For example, removal of the suctioning device from the manifold, such as for the purpose of replacing the suctioning device or attaching another accessory to the manifold, e.g. a manual resuscitation bag or a metered dose inhaler, cannot be accomplished without loosing manifold pressure and compromising the integrity of the respiratory system. Thus, respiratory support of the patient must be stopped whenever the suctioning device is removed from the manifold.
U.S. Pat. No. 4,351,328 to Bodai attempts to solve this problem by forming an opening in the ventilator manifold which is blocked by a pre-punctured resilient seal through which a suction catheter can be passed without substantially affecting the integrity of the system, i.e., without substantial gas exchange or pressure loss between the interior of the manifold and the atmosphere. The Bodai device, although allowing entry and removal of a suction catheter through a ventilator manifold during continuous respirator support of a patient, nevertheless fails to completely resolve the existing problem in the prior art. Specifically, the pre-punctured resilient material in the port allows only for the insertion of a suction catheter therethrough, and fails to accommodate a suctioning device which include a collapsible envelope for surrounding and protecting the catheter against contamination of its exterior surface. Further, there is no design consideration for the attachment of other accessory devices, such as a manual resuscitation bag or a metered dose inhaler, which are often necessary for use in the care of a patient.
Also, the system described by Bodai tends to cause mucous and other fluids from the patient's lungs and trachea to collect in the manifold as it is wiped from the prepunctured resilient seal when the suction catheter is removed therefrom. Because of this design problem, it is often necessary to replace the manifold of the respiration system more frequently than would otherwise be desirable.
There therefore exists a need in the art for a respiratory system which includes a ventilator manifold which allows simple attachment and detachment of accessory devices during continuous patient respiratory support without substantial pressure loss from the system and without substantial collection of body fluids in the manifold. And a respiratory manifold which can be easily clean of mucus and other fluids which may collect therein during use without the necessity of removing the accessory device therefrom.